I'd like to install another copy of Skyrim to my computer, possibly to another hard drive. I'd use this version to experiment with mods, ini tweaks (ugridstoload), etc...basically to see how far I can push the settings while still getting good performance.

Because it seems that Steam handles the install of Skyrim, regardless of whether one has a disc of the game, how might I go about this 2nd install process?

Thanks.

On another partition on your hard drive. Although, I think you would need another Steam account and purchase a second copy of Skyrim. Why not just make backups of your stable version. A simple file transfer would be much easier.

Actually, if you had another Windows installation on the same computer, you could install Steam and log in there with the same account. You could use that Windows partition as your sandbox for messing around in games and the other one as your main one. However, it may be best to back things up. Use 7z archives if you go that route, they give the best compression results.

I just make a "default install" folder, copy my clean install folder into it, and then make a few separate folders for different mod set ups, and swap out as necessary. What every I'm not using is zipped to save some space.